Hi! That was a bug in RC2 which was solved with developer's release 70. Even though you're on Rochen's servers, your site isn't running on suPHP as far as I can recall, that's why you got the bug (it's caused by an unwritable tmp directory). Can you try the dev release? If that doesn't help, try chmod'ing your tmp directory to 0777, run the update and then chmod it back to 0755.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!